Baghdad, Iraq ? Insurgents destroyed an American tank north of Baghdad, killing two U.S. soldiers, and wounded seven Ukrainians in the first ambush against the multinational force patrolling central Iraq, officials said Wednesday. The attacks were part of a dramatic upsurge in recent days.

U.S. policy in Iraq suffered another setback when the international Red Cross announced it was reducing its international staff in the country, two days after a deadly suicide car bombing at its Baghdad headquarters. The humanitarian group Medecins Sans Frontieres, or Doctors Without Borders, also announced it had pulled out workers.

The United Nations announced later Wednesday that it would withdraw staff, too.

“We have asked our staff in Baghdad to come out temporarily for consultations with a team from headquarters on the future of our operations, in particular security arrangements that we would need to take to operate in Iraq,” U.N. spokeswoman Marie Okabe said late Wednesday.

“This decision is not an evacuation, and it doesn’t affect the north.”

The Iraqi Governing Council blamed the upsurge on foreign fighters. The council on Wednesday called on neighboring countries to crack down on infiltrators crossing into Iraq and provide Iraqi authorities with information about former regime figures who may be hiding on their soil, according to a statement carried by the Arabic language television station Al-Jazeera.

Iraqi Foreign Minister Hoshyar Zebari will raise the border issue during a meeting of regional foreign ministers in Damascus, Syria next week, Al-Jazeera said.

In Washington, a U.S. defense official said Wednesday that a senior member of Saddam Hussein’s ousted government, Izzat Ibrahim al-Douri, was suspected of helping coordinate the attacks on American forces with members of Ansar al-Islam, a group linked to al-Qaida.

Early today, American soldiers carried out pre-dawn raids in Saddam’s hometown of Tirkit, detaining more than a dozen suspects, some believed to be involved in setting up a new terrorist cell, the U.S. military said.

Under the cover of darkness, 4th Infantry Division troops fanned out across the downtown, raiding six houses. U.S. forces had intelligence that the suspects were establishing a “new terrorist network” and planning attacks against coalition forces, Lt. Col. Steve Russell told The Associated Press after the operation.

Lt. Col. Steven Russell, center, commander of U.S. Army 4th Infantry Division 1-22 Infantry regiment, checks the ID of the suspect in a hood as other soldiers stand guard during a night raid in Saddam Hussein's home town of Tikrit, Iraq. Early today, U.S. soldiers detained four men who are believed to be involved in terrorist cells.